Since the completion of the Three Gorges Dam in 2003, its flood discharge and energy dissipation structures have withstood many flood tests. To further evaluate and summarize the design and actual performance of these structures, the discharge capacity of the Three Gorges Project was comprehensively assessed during the first regular dam safety inspection. The flow capacity of the power station units was verified using data from the Huanglingmiao Hydrological Station. The measured flow data from the power station indicate that the turbine output curve accurately reflects the actual flow rates of the left bank, right bank, and underground power stations. The actual discharge capacities of deep holes and surface holes were also evaluated and compared with their respective design values and model test results. The comparison reveals that the measured discharge capacity of deep holes matches the design value, while the measured discharge capacity of surface holes is slightly higher than the design value. However, the combined discharge capacity of deep holes and surface holes is basically consistent with the design value.